Mountain mint July 2020 Wildflower of the Month
Mountain mint(Pycnanthemum tenuifolium)
Mountain-mint
Pycnanthemum tenuifolium/muticum
By Helen Hamilton
John Clayton Chapter, VNPS
What’s not to like about a native perennial that is attractive to bees and butterflies, does not spread aggressively, and is deer-resistant? Mountain-mints bloom from June through August, with small white flowers rich in nectar that is food for many kinds of insects – butterflies, skippers, bees, beetles, flies and especially wasps. Flowers are tightly clustered on the ends of stems and their structure allows wasps and other short-tongued insects to feed easily.
Two species are common in our area. With very narrow leaves, Slender Mountain-mint (P. tenuifolium)has a delicate, somewhat airy appearance. This native perennial plant grows 1-3 feet tall, branching frequently to create a bushy effect. The leaves are up to 3 inches long and ¼ inch across. Each leaf is hairless, with a prominent central vein and smooth margins. Small white to lavender 2-lipped flowers are in dense clusters in the leaf axils or at the ends of slender, hairless stems.
The dark green leaves of Clustered Mountain-mint (P. muticum) are not thin, up to 2 inches wide, and have a strong spearmint aroma when crushed. The flowers are similar – the 2-lipped tubular flowers, each up to ½ inch wide, are in dense flat-topped clusters at the ends of the stems. Each cluster has a pair of showy silvery leaf-like bracts at the base. The entire plant looks like it has been dusted with powdery snow. Massed in groups, the effect is stunning – a clustered plant with tiny pinkish flowers buzzing with insects, surrounded by dark green leaves and snowy bracts.
Both Mountain-mints are easy to grow in the home garden, in full sun or part shade. Slender Mountain-mint prefers soils that are somewhat drier than the bogs and wet meadows where Clustered Mountain-mint occurs.
The flowers have no scent, but the leaves have a minty odor and taste. Deer usually don’t browse on Mountain-mints because of the minty taste; the foliage may contain anti-bacterial substances that disrupt their digestive process. The tiny seeds are disseminated by wind – they are too small to be of much interest to birds.
The common name “Mountain-mint” does not refer to a preference for the mountainous regions. Both Mountain-mints are found in most counties of Virginia, and range over the eastern and central regions of the U.S. and Canada. The genus name derives from the Greek pycnos for “dense” and anthemon, meaning “flower” and aptly describes the crowded flower clusters. The species name tenuifolium is derived from the Latin tenuis, meaning “thin,” a reference to the narrow leaves.
To learn more about native plants visit vnps.org